Draw buggy



DRAW BUGGY 2 Sheets-Sheet 2 Original Filed May 20. 1958 R. m N N Nm E o M m N. w. R m||rN NN A mw m E o. U, uw O km 10 44.3.4 IJIWUV ^w\\. 0 Ubm .uw O o United States Patent G 3,081,864 DRAW BUGGY Einar W. Nilsson, Belleonte, Pa., assigner to The McKay Machine Company, Youngstown, hio, a corporation oi' Ohio Original application May 20, i953, Ser. No. 736,622., now Patent No. 2,980,238, dated Apr. 18, 1961. Divided and this application Aug., 3l., i966, Ser. No. 53,204 6 Claims. (Cl. 20S- 24) The present application is a divisional application of my co-pending patent application Serial No. 736,622, tiled May 20, i958, entitled Draw Buggy, now U.S. Patent No. 2,980,238, which is assigned to the assignee of the present application.

The present invention relates generally to drawmg mechanism wherein elongated lengths of metal sections are drawn through suitable forming or restricting dies for reducing or forming the cross sectional area or shape of the metal sections and more particularly to an improved draw buggy of the kind adapted to be employed in such mechanism. It is, of course, common practice in the metal working arts to provide a stationary die block mounting a plurality of dies and an elongated frame or bench extending in the direction of drawing from the leaving side of the dies. A carriage is mounted on said frame or bench for longitudinal movement therealong and carries gripping means for engaging and holding the reduced or pointed end portions or" the metal sections which are initially loaded to project through the dies. The carriage, or draw buggy as it is commonly referred to in the art, is adapted to grip the projecting ends of the metal sections and then is moved outwardly along the frame or bench, by means of a hook mounted on the draw buggy engaging a link of a continuously driven chain, for example, thereby drawing the metal sections through the dies to reduce and/ or shape the same. Such mechanism may also include means for removing the draw metal sections or stock from the draw buggy, means for returning the draw buggy to its starting position adjacent the die block, automatic handling equipment for loading the pre-pointed metal sections into the die block and for removing and handling the drawn metal sections or lstock from the frame as well as suitable control apparatus for effecting generally automatic operation of the drawing mechanism in the desired manner. The general arrangement of this type of drawing mechanism is shown and described in the prior United States patents to Kerr and Andrews, Jr., et al., Nos. 2,404,234 and 2,331,953, respectively, which are representative of the prior practice in the art and are made of record for those desiring a more detailed description of the same.

It is the primary or ultimate object of the present invention to provide an improved draw buggy of the kind adapted to be employed with the above described type of drawing mechanism. Whenever a plurality of dies are employed and the draw buggy mounts a plurality on means for gripping the pre-pointed ends of metal sections, i.e.-in multiple drawing operations-it is necessary that all of the projecting reduced ends of the metal sections be properly gripped prior to movement of the draw buggy and the inability or" prior art apparatus to satisfactorily meet this condition has resulted in several serious problems. Failure of the gripping means to properly engage and grip one or more of the pre-pointed ends of the Patented ll/iair.7 19, 1963 ICC metal sections or stock is a frequent cause of delay in drawing operations and an interrupted draw may cause undesirable marking of the stock. These problems have prevented, to a certain extent, the realization of the etliciencies and economics inherent in drawing mechanism and methods of this general type and have somewhat limited the employment thereof.

It is another object of the invention to provide a draw buggy wherein the means for gripping the reduced ends of the metal sections is actuated to lirmly and positively grap the same prior to the movement of the draw buggy to draw the metal sections through the dies. As will be more fully apparent, the gripping means is actuated to grip the ends of the metal sections prior to the release of the hook carried on the draw buggy which engages the continuously driven chain.

A further object of the invention is to provide apparatus of the character described wherein a separate driving means for actuating the gripping means is mounted directly on the draw buggy and operative when energized to positively move the gripping means into gripping engagement with the ends of the metal sections prior to movement of the draw carriage. In accordance with this object, the draw buggy mounts an electric gear motor operating through new and novel linkage means to close the gripping means in relatively independent fashion whereby each of the metal sections is firmly gripped prior to drawing.

Another important object of the present invention is to provide improved means for powering or energizing theseparate driving means mounted on the draw buggy when the same is adjacent the die block. The draw buggy mounts a forwardly projecting connector and the die block mounts a mating connector so that when the draw buggy is against the die block the driving means is energized to actuate the gripping means. It will be noted that this arrangement is particularly advantageous since the driving means is energized at exactly the right time and remains energized to insure positive gripping of the projecting ends of the metal sections until the :actual drawing operation commences and the draw buggy moves outwardly from the die block.

A still further object of the invention is to provide improved grippingmeans for a draw buggy. Such gripping means comprises a plurality of sets of inwardly converging gripper bits and improved linkage means for moving the Sets of bits in relatively independent fashion to grip the pre-pointed ends of the metal sections. ln this manner each of the ends of the strip sections is firmly gripped irrespective of dilferences in the sizes and shapes of the said ends.

Yet another object of the present invention is to provide gripping means of the type indicated which is characterized by its almost complete lack of sliding friction. In previous gripping means the amount of sliding friction in the gripping means at the time the ends of the metal sections are being gripped is considerable and this sliding friction may prevent a good gripping action.

-Another object of the invention is to provide gripping means which is easily and readily removed for replacement and/or repairs. In this manner the drawing mechanism may be used for forming or shaping several diterent sized or shaped metal sections at one time or the entire gripping means may be changed to accommodate different metal sections in a fast and efficient manner thereby providing more versatile drawing mechanism.

An ancillary object of the present invention is to provide a draw buggy and gripping means therefor having the characteristics outlined above which is of simplified and economical construction but is yet well adapted to withstand continuous mill-type operations.

The above, as well as other objects and advantages of the invention, will become more readily apparent upon consideration of the following specication and accompanying drawing wherein there are disclosed certain illustrated embodiments constructed in accordance with the teachings of the present invention.

In the drawing:

FIGURE 1 is a plan view of an improved draw buggy, with a protective cover for a portion of the driving means removed, constructed in accordance with the teachings of the present invention;

FIGURE 2 is a side sectional view of the draw buggy taken along the section line II-II of FIGURE l;

FIGURE 3 is an enlarged fragmentary end sectional view taken along the section line III-III of FIGURE 1;

FIGURE 4 is a fragmentary plan view of the forward end of a draw buggy depicting an improved gripping means which is an improved form of gripping means from that shown in FIGURES l and 2;

FIGURE 5 is an enlarged fragmentary plan view showing specifically a portion of the gripping means of FIG- URE 4; and

FIGURE 6 i-s a side sectional view taken along the section line VI-VI of FIGURE 5.

Referring now to the drawing, and initially .to FIG- URES 1-3 thereof, the reference numeral 10 designates a generally rectangular unitary frame formed with bifurcated projections 11 adjacent each corner thereof that are spanned by transversely extending axles 12 which in turn journal wheels 13 by means of bearings 14. The frame is thus supported for movement by transversely spaced pairs of longitudinally separated wheels. The frame 10 has a large rectangular recess 15 for mounting thereon a gripping means 16, a driving means 17 for actuating the gripping means and a rearwardly projecting hook 18, all of which will be hereinafter more fully described. The draw buggy is adapted for longitudinal movement on a frame or bench 19 having spaced tracks, not particularly shown, for the wheels 13 and mounts a continuously driven chain thereon, also not shown. The bench 19 extends longitudinally in the direction of drawing from a die block, indicated schematically by the reference numeral 20, mounting a plurality of dies. In the normal and intended operation of such drawing mechanism the metal sections are first loaded into the dies with the reduced ends thereof projecting forwardly of the face of the die block 20. Then the draw buggy is returned to abutting relation with the die block and the driving means is actuated to move the gripping means to positively engage the protruding ends of the metal sections. After, and only after, the ends are properly gripped the hook 18 drops and engages a link of the driven chain and the draw buggy is moved outwardly of the die block thereby drawing the metal sections. When the drawing is completed the metal sections are removed, the hook 18 is disengaged from the driven chain and the draw buggy is returned to a position'adjacent the die block 20 for another drawing operation. It will be observed that the above described operation is well adapted for automatic and continuous cycling.

Considering now the gripping means 16 shown in FIG- URES 1 and 2 of the drawing, the forward ends of the frame 10 terminate in hook-like inturned portions 22 which engage vertical channels 23 formed on the opposite ends of a grip Vbit block 24 in the manner shown, The grip bit block 24 is provided with three pairs of converging guide channels 25 each adapted to slidably receive a grip bit 26 having a serrated forward end portion 27. The arrangement is such that the pairs of grip bits 26 may be slidably moved within the guide channels 25 in cooperating fashion to grip the ends of metal sections protruding from the die block 20. Each of the grip bit-s has a vertical bore 28 in the upper exposed rear surface thereof which is adapted to receive one downturned end of a U-shaped connecting rod 29. The other end of the U-shaped connecting rod is received within a vertical bore 30 of a collar 31 that is guided for sliding movement in a properly formed collar mounting portion 32 of the housing. It will be noted that the collar mounting portion 32 is formed with slots 33 to provide clearance for the connecting rods 29 and it is preferred, although not shown, that some means, such as projections extending from the collar guided in -suitable Ways, be provided for retaining the collars in proper alignment with the connecting rods. Secured to the forward end of each of the collars 31 is a forwardly projecting plunger 34 that passes through and is movable with respect to a suitably apertured crosshead 35 and terminates in a forward collar 36 the forward face of which is adapted to have bearing contact with the rear face of the grip bit 26 associated therewith. The forward collars 36 and the rear faces or surfaces of the grip bits are not rigidly connected but are adapted to contact each other in the manner shown. Surrounding each of the plungers 34 on opposite sides of the crosshead 35 are the coil springs 37 and 38 which extend between the rear faces of the forward collars 36 and the crosshead 35 and between the crosshead 35 and the collars 31, respectively, and are of such a diameter that they will not pass through the apertures within the crosshead.

The above described gripping means is similar to that shown and described in the aforementioned Kerr patent, No. 2,404,234, and it will be observed that forward longitudinal movement of the crosshead 35 along the axes of the plungers 34 forces the plungers to move along their longitudinal axes through connections provided by the coil springs 37 and consequently the grip bits 26 move into their operative positions. Rearward longitudinal movement of the crosshead causes the gripper bits to retract through drive connections comprising the coil springs 38, collars 31 and connecting rods 29. In effect, each of the grip bits 26 is independently and yieldably mounted since a plunger 34, collar 31, coil springs 37 and 38 and connecting rod 29 are provided for each individual grip bit in order that the ends of metal sections are properly gripped regardless of differences in the size and shape thereof.

Rigidly connected to the crosshead 35 adjacent the opposite ends thereof are the forward ends of a pair of identical and generally parallel drive rods 40. Each of the drive rods 40 is accurately guided for longitudinal movement by apertures 41 and 42 provided in the collar mounting portion 32 and forward end portion of the frame, respectively, in the manner shown. The drive rods 40 extend almost the entire length of the frame 10 and are further guided for longitudinal movement intermediate their ends by a pair of integral apertured bosses 43 projecting into the recess 15 from the frame 10 and by a pair of elongated and shouldered `spacers 44 carried thereby. The rear end portion of each of the drive rods 40 is slidably received within a tubular fitting 45 having a segment of a rack 46 on the upper face of the forward end portion thereof and an enlarged longitudinally extending bore y47 adjacent its rear end of greater diameter than the diameter of the drive rod. The tubular lfittings 45 are suitably guided for longitudinal movement with respect to the frame 161 by properly formed portions thereof as is readily apparent. Received within the bore 47 of each of the tubular fittings 45 is an externally threaded tubular portion 49 of a projecting latch 50 Whose use willbe hereinafter more fully explained. The threaded tubular portion 49 of each of the latches 50 is held in rigid relation with respect to the tubular fitting 45 associated therewith by means of a lock nut 5l. It will thus be seen that the rear ends of the drive rods are slidably received within the tubular assemblies including the fittings 45 and the latches 5i) while these assemblies are adapted for longitudinal movement with respect to the frame l() of the draw buggy. As shown in FIGURE 3 of the drawing the frame l@ is formed with inwardly projecting channels adjacent the inner edges of the recess l5 for guiding the projecting ends of latches 5t) during movement thereof. Each of the drive rods 40 has an integral shoulder S3 thereon which is received within the bore 48 defined by the tubular fitting 4S associated therewith and disposed on opposite sides of this shoulder in encircling relation with the drive rod and within the confines of the tubular bore are spaced coil springs 54 and 55. The shoulders '53 form, in effect, abutments and it will be noted that if the tubular fittings and latches are moved to the left from their retracted positions the drive rods will also be moved to the left under the influence of the coil springs while when the tubular fittings and latches are moved to the right the drive rods are also driven by the coil springs. This provides, in essence, a resilient or yieldable driving connection between the tubular fittings and the crosshead 35 and latches Si) carried by the drive rods.

Positioned forwardly of the tubular fittings d5 between these last mentioned members and the spacers 44 in encircling relation with the drive rods 46' are a pair of return coil springs 56 whose function it is to return the tubular fittings and consequently the drive rods to xtheir retracted positions in a manner to be further explained.

The driving means for actuating the gripping means comprises an electric gear motor 5S having a rearwardly extending drive shaft 59 mounted within the recess 15 of the frame directly behind the gripping means. Keyed to the drive shaft 59 is a bevel gear 6@ which mates with a normally disposed bevel gear 6l mounted intermediate the ends of a transversely extending splined and shouldered shaft 62 whose ends are journaled by bearings 63 in cup shaped bearing carriers 64 rigidly received within the frame llt). Also mounted on the shouldered shaft 62 adjacent the ends thereof and adapted for rotation therewith are a pair of wheel gears 65 having gear teeth'along a portion of their circumferences adapted to mesh with the racks 46 on` the tubular ttings 45 as clearly shown in FIGURE 2 of the drawing. It will thus be seen that upon energization of the electric gear motor 58 the tubular fittings 45 and consequently the drive rods 40 and the cross head 35 and latches 5d mounted on the drive rods will be moved in a longitudinal direction by virtue of the meshing racks 46 and wheel gears 65 which are interconnected by the above described gearing with the electric gear motor 53. The driving means is so constructed and employed `and the drive rods, tubular fittings and latches are so guided that the drive rods will be actuated in exact synchronism and any relative movement between these members is precluded.

One of -the important aspects of the present invention is the means employed for energizing the gear motor Se for actuating the gripping means `and moving the latches. This means comprises a suitable electrical connector 66 mounted on and projecting from the forward end `of the frame 10. The electrical connector 66 is connected by suitable conduits, not shown, with the gear motor and the forward face thereof is aligned with the forward edge of the grip bit block. A mating electrical connector, not specifically shown, is mounted on the die block 2@ and the arrangement is such that when the draw buggy is moved into abutting relation with the' die block an electrical circuit is completed due to the engagement of the two connectors and energizing potential is thus supplied to the gear motor 58 -to actuate the same thereby causing movement of the drive rods and actuation of the gripping means. However, when the draw buggy is not in abutting relation with the die block the gear motor is not energized and in this manner, as will be further explained, the driving means is posi-tively energized only when needed and complicated controlling apparatus, such as switches, sliding contacts, etc. is not required. It should be understood, of course, that means other than the electric gear motor-such as a fluid motor, for examplecould be employed with a similar breakable fluid connection and such modification is within the scope and intent of the present invention.

The hook 18 is formed with an integral` boss on its rear end and is pivotally mounted in a rearwardly extending manner for vertical pivotal movement within the recess 15 by means of a transversely extending pivot pin 63 spanning the recess. Intermediate the boss and the downturned projection which is adapted toengage a link of the continuously driven chain the hook increases in transverse dimension and is provided with a transversely extending and properly formed rigid back-up element 69 which spans the recess l5 adjacent the rear ends of the latches Si). The hook and back-up element are suitably aperture'd to define a transverse bore 70 which receives the transversely extending latch rod 71 and it will be noted that appreciable portions of the circumferential surface area of the latch rod adjacent the ends thereof and overlying the latches are exposed while the portions between the hook proper and the end portions are completely exposed. Mounted on the latch rod on these last mentioned portions on opposite sides of the hook proper are a pair of downwardly depending cams 72 whose function it is to cooperate with cam members, not shown, mounted on the bench for raising the hook. The ends of the latch rod 71 overlie the ends of the latches and when the latches are in their rearmost positions the hook cannot be lowered because of the latch rod engages and rests upon thel upper surfaces of .the latches. However, when the latches are moved forwardly a sufficient distance the hook is allowed to drop to engage a link of the driven chain. The latch rod 71 is retained within its bore 70 by a pair `of end cover plates '74y bolted to the ends of the backup element 69 and this arrangement is particularly advantageous since it provides. for quick removal and replacement of the latch rod which will be subjected to constant hammering and shock forces when the Vhook is dropped on the latches. It is noted that the back-up element provides considerable -structural support and reinforces the latch rod to provide an assembly adapted to withstand hard and continuousl usage.

Operation Considering now the operation of the draw buggy above described, it is assumed that a drawing `operation has been completed and the draw buggy is being returned along the bench toward the die block. At this time the grip bits 26 are in their retracted or inoperative positions and the hook 18 is in the raised position with the ends of the latch rod 71 resting on the upper surfaces of the rearwardly extended latches 50 whereby the hook is free of the drive chain. The gear motor 58 is, of course, de-energized at -this time. It is also assumed that metal sections have been loaded in the dies with the pre-pointed ends thereof projecting past the face of the die block.

As the draw buggy abuts against the face of the die block the electrical connector 66 engages the connector mounted on the die block thereby completing an energizing circuit for the gear motor 58. Energization of the gear motor causes rotation of the shouldered shaft 62 and the wheel gears 65 carried thereby to begin to moveA Ithe tubular fittings 45 and the latches 50 in a forward direction toward the die block. As the tubular fittings and latches move forward the ends of the latches engage the rear ends of the coil springs 55 anda driving force is transmitted to the drive rods 40 through these yieldable coil springs acting against the shoulders 53. As the spense@ tubular fittings are moved forward the return coil springs 56 encircling the drive rods are compressed and exert a force tending to move the tubular members and latches to their retracted positions. As the drive rods move forward the crosshead 35 carried directly lthereby is also caused to move and, through springs 37 and plungers 34, exerts a force -on the various grip vbits 26 to rnove the same inwardly and firmly about 'the projecting prepointed ends of the metal sections. It should be apparent that the entire driving connection from the gear motor 58 to the individual grip 1bits is yieldable and resilient due to the inclusion of the various coil springs and this allows each of the ends of the metal sections to be properly and independently gripped.

With the ends of the metal sections thus gripped the latches 50 have not as yet moved forward to such an extent that the hook is free to drop. However, as the tubular members and latches continue to move forward a short distance-thereby further compressing the springs 55 as the ends of the metal sections are now properly gripped and this exerts a greater gripping force on the ends of the metal sections through the drive rods-the latches move out from under the latch rod. The hook 18 now falls to engage a link of the driven chain so that the draw buggy is propelled along the bench away from the die block. It should be understood that the latches are of such a length and are so designed with respect to the other portions of the draw buggy that they do not move out from under the latch rod unless and until the end portions of the metal sections are properly gripped.

When the hook falls it engages a link of the driven clrain and as the chain takes up the load it rises to the elevation of the transversely extending pivot pin 68 thereby lifting the latch rod suiciently above the latches to allow for the return movrement of the latches. As soon as the draw buggy begins to move the gear motor 5S iS As soon as the gear motor is de-energized and the hook is raised the elongated coil return spr-ings 56 gain control and exert a force sufficient to move the tubular fittings 4S and the latches 5t) to their original positions with the latches preventing downward movement of the hook. ft will be noted that the axis of the pivot pin 68 is above the plane of the upper surfaces of the latches so that the movement of these members does not interfere with the drawing operation. The tubular fittings and latches will be returned to their original positions in a very fast manner under the action of the return coil springs 56 and it may be desirable to provide means for limiting or braking the torque of the motor during latching the hook. While the tubular iittings and latches are moving to their original positions the compressive forces on the coil springs 55 will be relieved and after suicient travel the coil springs 54 will act on the shoulders 53 to transmit a retractive force on the drive rods iti thereby causing the same to move in a rearward direction. The crosshead 35, which is rigidly connected to the ends of the drive rods, will also move in the same direction and this movement is suicient to relieve the coil springs 37 and to compress the coil springs 38 whereby the grip bits are urged to their retracted orginoperative positions through the collars 31 and U-shaped connecting rods 29. Of course, the tension exerted by the metal sections being drawn is much greater than that applied by the coil springs 38 so that the grip bitsV remain in tight gripping relation with respect to the ends of the metal sections. It is noted that the yieldable and resilient connections provided by the various coil springs employed throughout the draw buggy insure that .the actual drawing operation will be completed in a continuous and uninterrupted manner.

To provide means to raise the hook 13 during move- 8 ment of the draw buggy irrespective of the load and tightness of the driven chain the pair of cam members are positioned along the tracks and are adapted to be engaged# by the depending cams 72. fIf the hook is down when the `cam members are reached the lower surfaces of the cams ride up the inclined upper surfaces of the cam members thereby raising the hook suiiiciently to permit retraction of the tubular ttings, latches and drive rods.

As the metal sections leave the dies the tension on the properly shaped and/or formed metal sections and the grip bits will be immediately released in a sudden manner and the compressed coil springs 38 will gain control to swiftly move the grip bits to their inoperative positions. At the same time the draw buggy will be accelerated in a direction away from the die block causing the chain to fall from the hook and the hook will fall until the latch rod strikes the upper surfaces of the latches thereby retaining the hook in its original raised position. The draw buggy is thus conditioned for another drawing operation with the latches, tubular fittings, hook, drive rods and grip bits in their retracted positions and these elements will remain in these positions until the gear motor 5S is again energized. After unloading of the drawn metal sections the draw buggy may be returned to a position adjacent the die block for another drawing cycle.

`ln considering the above described operation of the draw buggy of the present invention it should be apparent that the same provides many advantages. Of particular importance is the use of the v-arious coil springs which not only insure proper gripping action by providing yieldable and resilient driving connections but also provide shock absorbing means for dissipating the shock forces attendant to drawing apparatus upon the metal sections leaving the dies, etc. The gear motor and the gearing provides an excellent means for actuating the grip bits wherein the ends of the metal sections are firmly and positively gripped prior to movement of the draw buggy. The means for energizing the driving means, although extremely simple, is advantageous since the driving means is energized only as required while yet insuring the proper gripping of the metal sections. The hook and latching arrangements therefor are well adapted for drawing operations and the concept of a latching means operative in response to closure of the grip bits a short time after the ends of the metal sections are grippedris especially important.

Grz'ppz'ng lMeans In FIGURES 4-6 of the drawing there is shown an improved gripping means for a draw buggy constructed in accordance with the teachings of the present invention. The draw buggy embodied in these views of the drawing is, with the exception of the gripping means, the same as that described above and in order to eliminate unnecessary repetition in the specification like parts are designated by the same reference numerals.

Mounted for sliding movement within each of the guide channels 2S of the grip bit block 24 is a grip bit holder 86 that carries on the forward face thereof, by means of a dovetailed channel, a grip bit element 81 having a serrated face portion 82. The grip bit holder has a vertical through bore 83 in the exposed rear end thereof which serves as a retaining socket for a generally cylindrical pivot block 84. A snap ring 85 is used to close the bottom of the through Vbore 83 and to Vretain the pivot block 84 within the thus deiinedsocket. The extreme rear end portion of the grip bit holder 8th has a vertically extending slot 86 which communicates with the vertical through bore and exposes the pivot block from the rear. In addition to the vertical slot the rear end portion of the grip bit holder and the exposed portionV of the pivot block are formed or machined to denne a finsto-conical bore 87 whose use will be hereinafter more fully apparent.

Extending longitudinally with respect to the frame of the draw buggy is an actuating rod 88, the forward end portion of which is threadably attached and pinned t0 9, the pivot block 84. The actuating rod extends axially within the above dened frustro-conical bore 87 and is slidable within a second generally cylindrical pivot block 89 intermediate its ends. The second pivot block 89 iS received within a cup-shaped holder 90 having a vertically extending slot 91 therein to define openings on its opposite sides. The cup-shaped holder 90 and the second pivot block 89 are each machined or formed to provide a pair of frustro-conical longitudinally extending openings 92 on opposite sides thereof adjacent the vertically extending slot to provide clearance for the movement of the actuating rod 88.

The rear end portion of the actuating rod 88 is threaded and mounts `a retaining nut 93. Also provided in encircling relation with respect to the actuating rod 88 are a pair of compression coil springs 94 and 95the rst of these springs extending from the pivot block 84 to the pivot block 89 and the second of these members being positioned between the pivot block 89 and the retaining nut 93.

As is readily apparent from the drawing, the draw buggy comprises three pairs of grip bit holders and elements and each of these members are provided with actuating means-including the pivot blocks, cup-shaped holders, actuating rods, retaining nuts, compression coil springs, etc.-as described above. In this manner of providing separate actuating means for each of the grip bit holders and elements it is insured that all of the pre-pointed ends of the metal sections will all be properly gripped prior to movement of the draw `buggy thereby greatly facilitating the drawing operation.

The plurality of cup-shaped retaining members 90 are rigidly mounted in aligned fashion on a movable and transversely extending crosshead 97 which is an `angle member and has a plurality of properly positioned apertures 98 in the upstanding wall thereof to permit the unobstructed passage of the plurality of actuating rods '88 therethrough. The crosshead 97 is rigidly mounted on the forward ends of the drive rods 40 and, of course, is movable with these members.

In the operation of the gripping means of FIGURES 4-6 the draw buggy is returned to the die block and the gear motor 5S is energized to move the drive rods forward in the manner heretofore described. Movement of the drive rods causes the crosshead 97 to be carried forward-the actuating rods 88 are slidably received within the pivot blocks Z39-thereby exerting a force through the coil springs 94 .against the pivot blocks 84. This causes the grip bit holders 80 to slidably move within their guide channels and the grip vbit elements to forcibly and positively engage the protruding prepointed ends of the metal sections. The position of the various apparatus when the crosshead is in its most forward po-sition is shown in FIGURE 4 of the drawing.

Probably the most important advantage of the gripping means of FIGURES 4-6 is the elimination of a substantial amount of sliding friction. It will be observed that in the gripping means described in connection with FIGURES l and 2 of the drawing that the cooperating pairs of grip bits 25 move in a converging manner while the plungers 34 and collars 31 and 35 are `guided for and limited to longitudinal movement and because of these angularly related directions of guidance and movement there must be relative movement in a transverse plane between the rear ends of the grip bits and the forward faces of the collars 36. This relative movement results in substantial sliding friction in the transverse plane since these members are under pressure in the longitudinal direction and this problem is most acute at the exact moment the grip bits engage the ends of the metal sections. The sliding friction resulting `from this relative movement is considerable and may prevent the proper gripping of the ends of the metal sections thereby causing a serious delay if one or more of the metal sections is not initially gripped or the draw is interrupted by release of one or more of the metal sections.

In the gripping means of FIGURES 4 6, however, such sliding friction in the transverse direction is entirely eliminated since as the grip bit elements 8l move inwardly the actuating rods 88 will pivot or swing as needed in a free and easy manner due to the pivotal connections between the `grip bit holders, the crosshead and the actuating rods. Each of the pivot blocks is freely pivotable about its vertical axis and the frustro-conical bores are of such size and shape to permit swinging movement of the actuating rods. Of course, the transverse swinging movement of the actuating rods is not great enough to cause interference between adjacent actuating rods. In essence, the gripping means is characterized by its complete lack of sliding friction in the transverse direction and proper `and positive gripping of the ends of the metal section is always insured.

A short time after the ends of the metal sections are properly gripped the hook of the draw buggy is dropped to engage a link of the `driven chain and the draw buggy moves away from the die block thereby de-energizing the gear motor 58. The previously compressed return coil springs 56 gain control and drive the drive rods 40 and the crosshead 97 to the rear thereby relieving the coil springs 94 and compressing the coil springs 95 which exert forces tending to retract the grip bit elements to their inoperative positions. The metal sections are under considerable tension during drawing and this precludes retraction of the grip belt elements during drawing operations. When the metal sections leave the dies the released energy of the metal sections in tension and the force of the compressed coil springs 9S will quickly move the grip bit elements to their retracted positions where they will remain until the gear motor is again energized.

The above described gripping rneans of FIGURES 4-6 is characterized by its simplicity of construction but yet is operable in an improved manner. One important aspect thereof is the extreme ease with which the gripping means may be removed and replaced. The pivot `blocks 84 and 89, springs 94 and 95, retaining nut 93 and actuating rod 88 form a self-contained assembly for each of the grip bit elements which may be lifted directly from the draw buggy due to the provision of the various vertically extending slots 86, 91 and S8 in the grip bit holders, cup-shaped holders and crosshead, respectively.

Although I have accomplished the objects initially set forth, it should be apparent that many changes may be made in the illustrated embodiments of the invention without depanting `from `the teaching thereof. Accordingly reference should be had to the following appended claims in determining the true scope and intent of the invention.

I claim:

1. Gripping means for drawing mechanism comprising a pair of converging guide channels, a pair of grip bit holders guided for sliding movement within said channels, a longitudinally movable actuating rod for each of said grip bit holders, said actuating rods being pivotally attached to said grip bit holders, a transversely extending longitudinally movable crosshead, said actuating rods Ibeing pivotally and slidably mounted with respect to said crosshead, and yieldable means received over said actuating rods on opposite sides of said crosshead.

2. Apparatus according to claim 1 further characterized in that said crosshead mounts a plurality of cup-shaped holders, a cylindrical pivot block received within each of said cup-shaped holders, and said actuating rods passing through Said pivot blocks whereby said actuating rods are slidable with respect thereto and are pivotal about vertical axes.

3. Gripping means for drawing mechanism comprising a pair of converging guide channels, a pair of grip 'bit holders guided for sliding movement within said channels, a longitudinally movable actuating rod for each of said grip bit holders, said actuating rods being pivotally attached to said grip bit holders, .a pivot 'block for each of said actuating rods pivotally mounting the same outwardly of said rgrip bit holders, and means to move said pivot blocks.

4. Apparatus according to claim 3 further characterized in that said actuating rods are slidable in a longitudinal direction with respect to said pivot blocks, and yieldable means positioned between said grip bit holders and said pivot blocks.

5. Apparatus according to claim 3 further characterized in that said means to move comprises a transversely extending crosshead, a plurality of eup-shaped members mounted on said crOSShead, said pivot block being received Within said cup-shaped holders, and said cupshaped holders and said grip bit holders `being provided with longitudinally extending bores adjacent said actuating rods to permit free swinging movement thereof.

6. Apparatus according to claim 5 further characterized in that said grip bit holders and said cup-shaped holders are pr-ovided with vertical slots whereby said actuating rods, yieldable means and pivot blocks may be removed as an assembled unit.

Kerr July 16, 1946 Fredriksson July 21, 1959 

1. GRIPPING MEANS FOR DRAWING MECHANISM COMPRISING A PAIR OF CONVERGING GUIDE CHANNELS, A PAIR OF GRIP BIT HOLDERS GUIDED FOR SLIDING MOVEMENT WITHIN SAID CHANNELS, A LONGITUDINALLY MOVABLE ACTUATING ROD FOR EACH OF SAID GRIP BIT HOLDERS, SAID ACTUATING RODS BEING PIVOTALLY ATTACHED TO SAID GRIP BIT HOLDERS, A TRANSVERSELY EXTENDING LONGITUDINALLY MOVABLE CROSSHEAD, SAID ACTUATING RODS BEING PIVOTALLY AND SLIDABLY MOUNTED WITH RESPECT TO SAID CROSSHEAD, AND YIELDABLE MEANS RECEIVED OVER SAID ACTUATING RODS ON OPPOSITE SIDES OF SAID CROSSHEAD. 